Semiconductor wafer processing system

ABSTRACT

A processor for processing integrated circuit wafers, semiconductor substrates, data disks and similar units requiring very low contamination levels. The processor has an interface section which receives wafers in standard wafer carriers. The interface section transfers the wafers from carriers onto novel trays for improved processing. The interface unit can hold multiple groups of multiple trays. A conveyor having an automated arm assembly moves wafers supported on a tray. The conveyor moves the trays from the interface along a track to several processing stations. The processing stations are accessed from an enclosed area adjoining the interface section.

This is a divisional of co-pending U.S. patent application Ser. No.08/236,424, filed Apr. 28, 1994, now U.S. Pat. No. 5,544,421.

TECHNICAL FIELD

This invention relates to automated semiconductor wafer processingsystems for performing liquid and gaseous processing of wafers. Suchsystems can be used to process semiconductor wafers, data disks,semiconductor substrates and similar articles requiring very lowcontaminant levels.

BACKGROUND OF THE INVENTION

The processing of semiconductor wafers has become of great economicsignificance due to the large volume of integrated circuits, data disks,and similar articles being produced.

The size of features used in integrated circuits and data disks havedecreased significantly, thus providing greater integration and greatercapacity. This has been possible due to improved lithography techniquesand improved processing.

The reduction in feature size has been limited by contamination. This istrue because various contaminating particles, crystals, metals andorganics lead to defects in the resulting products. The limitations onfeature size caused by contaminants have prevented full utilization ofthe resolution capability of known lithography techniques. Thus thereremains an acute need for improved methods and systems for processingsemiconductor wafers, data disks and similar articles requiring very lowlevels of contamination during processing.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below withreference to the accompanying drawings, which are briefly describedbelow.

FIG. 1 is a perspective view showing a preferred semiconductor waferprocessing system according to this invention.

FIG. 2 is a perspective view showing top portions of a wafer holdingtray used in the processing system of FIG. 1.

FIG. 3 is a perspective view showing bottom portions of a wafer holdingtray used in the processing system of FIG. 1.

FIG. 4 is a perspective view showing the tray of FIG. 2 loaded withwafers.

FIG. 5 is a perspective view showing a prior art industry standard wafercarrier loaded with wafers. The wafer holding tray of FIG. 2 ispositioned below the wafer carrier.

FIG. 6 is a perspective view showing portions of a wafer handlingsubsystem used in the processing system of FIG. 1.

FIG. 7 is a perspective view of the subsystem of FIG. 6 moved into aninitial loading position with wafer carriers containing wafers loadedthereon.

FIG. 8 is a perspective view showing the subsystem of FIG. 6 moved intoa further position wherein empty wafer trays are passing through a traypass-through opening.

FIG. 9 is a perspective view showing the subsystem of FIG. 6 moved intoa further position wherein the wafer trays have been elevated up throughthe wafer carriers to lift wafers from the carriers onto the trays.

FIG. 10 is a perspective view showing the subsystem of FIG. 6 moved intoa still further position wherein the wafer trays with wafers arepositioned upon an upper carriage.

FIG. 11 is a perspective view showing the subsystem of FIG. 6 with theupper carriage and supported wafers and wafer trays positioned forholding until subsequently processed in the system processing chambers.

FIG. 12 is a perspective view of the subsystem of FIG. 6 in a positionsimilar to FIG. 7 with the emptied wafer carriers ready for removal andreplacement by loaded wafer carriers so that a second group can betransferred in a process similar to that illustrated by FIGS. 7-12.

FIG. 13 is a perspective view showing the wafer processing system ofFIG. 1 with a robot conveyor loading a tray of wafers.

FIG. 14 is a perspective view similar to FIG. 13 with the robot conveyorrelocated and preparing to install the tray wafers into a centrifugalprocessing module.

FIG. 15 is a perspective view similar to FIG. 14 with the robot extendedinto a loading position wherein the tray of wafers is installed in thecentrifugal processing module.

FIG. 16 is a view showing mechanical arm portions of the robot conveyorshown in FIG. 1 extended into a laid-out position for purposes ofillustration.

FIG. 17 is a view showing how the view shown in FIG. 16 is partitionedinto the enlarged detail sectional views shown in FIGS. 18-28.

FIGS. 18-28 are enlarged detailed sectional views showing differentportions of the mechanical arm of FIG. 16.

FIG. 29 is a top view showing a hand portion of the mechanical armassembly with a tray of wafers loaded thereon.

FIG. 30 is a front view showing the hand portion of FIG. 29.

FIG. 31 is an isometric view of a preferred centrifugal processing rotorused in the centrifugal processing modules shown in FIG. 1.

FIG. 32 is a front view of the rotor shown in FIG. 24.

FIG. 33 is a front view of the rotor as shown in FIG. 32 with a wafertray held within the rotor.

FIG. 34 is a schematic view showing functional blocks of the preferredcontrol system used in the processor of FIG. 1.

FIG. 35 is a perspective view showing important components of themechanical arm assembly shown in FIG. 13.

FIG. 36 is a front elevational view of an alternative processoraccording to this invention.

FIG. 37 is a side elevational view detailing an alternative processingstation used in the processor of FIG. 36.

FIG. 38 is a top view detailing the alternative processing station shownin FIG. 37.

FIG. 39 is a rear elevational view detailing the alternative processingstation shown in FIG. 37.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This disclosure of the invention is submitted in furtherance of theconstitutional purposes of the U.S. Patent Laws "to promote the progressof science and useful arts" (Article 1, Section 8).

Processor Generally

FIG. 1 shows a preferred processing system 40 according to thisinvention. Processing system includes a basic frame 41 which providesstructural support for related components. Processor 40 has twofundamental sections, one of which is the interface section 43. Theother fundamental section is the processing section 44.

The frame supports an enclosure envelope 45 which in FIG. 1 is shownpartially removed adjacent the processing section for purposes ofillustration. The enclosure envelope encloses a working space 46 withinportions of processor 40. Wafers 50 are held and maneuvered within theenclosed working space. The wafers are moved between multiple processingstations 71-73 contained within the processing section 44. The workingspace can be supplied with a purge gas and operated at either slightlyelevated or slightly reduced pressures relative to ambient atmosphericpressure.

The upper portions of processor 40 are provided with an interface filtersection 38 and a processing filter section 39. These filter sectionspreferably employ HEPA type ultrafiltration filters. Air movingequipment forces air through the filters and downwardly into the workingspace to move contaminants downwardly and out through the back side ofthe processor.

The multi-station processor 40 also preferably has a process stationmaintenance section 53 which is separated from the work space 26 byportions of the enclosure envelope 45. Processor 40 also preferably hasan instrumentation and control section 54 mounted rearwardly from theinterface section 43. Control section 54 preferably includes variouscontrol equipment used in processor 40.

Maintenance section 53 and control section 54 are of potentially highercontamination levels due to the presence of various equipment componentsassociated with the processing stations. The processor 40 isadvantageously mounted in a wafer fabrication facility with clean roomaccess to the front of the processor along front panel 48. Themaintenance and control sections are preferably accessed from the rearof processor 40 through a gray room adjacent the clean room. Such grayrooms have fewer precautions against contamination than the clean room.This configuration reduces plant costs while allowing access to portionsof the processor more typically needing maintenance.

The front of processor 40 includes a front control panel 57 allowingoperator control from the clean room. Control panel 57 is advantageouslya touch screen cathode ray tube control display allowing finger contactto the display screen to effect various control functions. Controlsection 54 also preferably includes a secondary control panel (shownschematically in FIG. 34) which faces rearwardly into the gray room sothat operation can be affected from either front or back of the machine.All control functions and options are displayed upon the control panelsto effect operation and set up of the processor.

As shown, wafers 50 are supplied to and removed from the enclosed workspace 46 of processor 40 using interface section 43. Wafers are suppliedto the interface section in industry standard wafer carriers 51(detailed in FIG. 5). The wafer carriers are preferably supplied ingroups, such as a group of four carriers. The groups are placed upon acantilevered shelf 101 forming a part of a first carriage 100. Shelf 101extends through an interface port 56 which is controllably opened andclosed using a interface port door 59. Adjacent the interface port andcontrol panel is a view window 58 through which a human operator can seeoperation of processor 40. FIG. 1 shows two wafer carriers 51 positionedupon the cantilevered shelf 101. There are two additional positionsavailable for two additional carriers which are left unloaded in FIG. 1.

Wafer Tray

Refer to FIGS. 2 and 3 which show the novel wafer tray 60 in greaterdetail. Wafer tray 60 includes an upper surface 61 and a lower surface62. The tray also has a first end 63 and a second end 64. Sides 65extend between the first and second ends. Additional features of thetray surfaces will flow be more fully detailed.

Upper surface 61 has a series of wafer tray receivers 66. Wafer trayreceivers 66 each comprise a semicircular groove or channel havingdownwardly converging receiver sides 67. The converging receiver sides67 adjoin to a receiver bottom section 68 which is a relatively narrowslot having substantially parallel slot walls. The slot section is sizedto provide a width about 0-10% greater than the thickness of the waferswhich are being received therein. The receiver bottom or slot sectionhas bottom surfaces 69. The lower portions of the slot sections 68 areformed so as to be intermittently closed at slot bottom surfaces 69 andopen along receiver drain apertures 70 (FIG. 3). The slot bottomsurfaces 69 exist along longitudinal foundation bars 75 and side railportions 76. The particular number of wafer tray receivers 66 in anyparticular tray 60 is variable. Typically, there will be 25 or 50 waferreceivers in order to correspond with the capacity of associated wafercarriers 51 being used in other parts of the fabrication plant.

The upper surfaces of wafer tray 60 also preferably include side landportions 79. The side land portions are formed to reduce overall heightof the tray while maintaining the general semicircular receiver shape.The overall width of tray 60 is appropriately sized so that more thanapproximately 50° of arc are seated, more preferably approximately60°-80° of arc are encompassed for seating the wafers in receivers 66.Even more preferably the arc of the receiving channels is approximately65°.

The wafer tray ends 63 and 64 are preferably planar and perpendicularrelative to a longitudinal axis 80 (FIG. 4) which extends perpendicularto the receiving grooves along the center point of the receiving groovearcs defined by bottom surfaces 69. Longitudinal axis 80 also coincideswith the centers of the wafers 50 supported on the wafer tray. Tray ends63 and 64 are advantageously provided with apertures 88 for receiving atool therein to allow handling of the trays with minimum contact, suchas during cleaning.

Wafer tray 60 has side rails 76 which extend along both sides. The siderails have outer side surfaces 65 which are advantageously formed toprovide tray support features 80. As shown, tray support features 80include a tray side channel 81. Tray side channel 81 has a downwardfacing bearing surface 82 which bears upon supporting tools andequipment as explained more fully hereinbelow. Adjacent to surface 82,is an outwardly facing channel base surface 83. Bearing surface 82 ispreferably constructed to form an included angle of approximately 120°of arc relative to the channel base 83. Channel 81 further includes anupwardly facing third surface 84 which serves to complete the channelshape of the tray support features and provides increased structuralengagement between the wafer tray and equipment which engages the trayusing the tray side channels 81.

The lower surface 62 of tray 60 is preferably formed with a downwardlyfacing contact or foot surface 86. As shown, foot surface 86 defines afootprint with five longitudinal segments associated with side rails 76,longitudinal bars 75, and end panels 63 and 64. The lower surface of thetray also is preferably constructed to have longitudinal base recesses77 between bars 75 and side rails 76. Processing fluids drain from thewafers 50 and wafer tray 60 through the receiving slot openings 70 andbase recesses 77.

The novel wafer trays 60 provide improved processing of wafers inprocessor 40. The improvements include improved access of processingfluids to the surfaces of wafers 50. The improved access of processingfluids occurs because there is less coverage of the wafers as comparedto prior art carriers 51. Only relatively small marginal edge portionsalong the arc of the receivers is covered. Thus allowing almost fullaccess to the faces of the wafers by processing fluids. The improvedaccess to processing fluids in turn results in reduced processing timesand greater uniformity and effectiveness of the processes upon thesurfaces being treated. Wafer tray 60 also results in a small combinedsize of the wafer batch within processor 40. This translates into a muchsmaller overall size of processor 40 and reduced floor spacerequirements in clean rooms and adjacent gray rooms. Since the cost offloor space in these facilities is very high, the installed cost of theprocessing system 40 is kept relatively lower. These factors allattribute to better yields, improved quality and reduced costs ofproduction.

Standard Wafer Carrier

Processor 40 is designed to work in conjunction with a standard industrywafer carrier which is illustrated in FIG. 5. Such carriers areavailable from a number of supplying manufacturers. Carrier 51 has aholding trough 34 with a series of edge receiving receptacles 35 alongside walls 36. End walls 37 are typically provided with handles 38. Thebottom of carrier 51 is provided with a bottom opening (not shown) whichis rectangular and defined between base rails 39. FIG. 5 shows a wafertray 60 positioned beneath wafer carrier 51 aligned to pass up throughthe bottom opening of the carrier. Wafer tray 60 is sized to passthrough the bottom opening.

Interface Section

The interface section 43 takes the wafers from the wafer carriers andinstalls them onto the specially constructed wafer trays 60. The wafertrays provide improved processing of wafers 50. The interface sectionalso preferably provides a holding or inventorying capability for bothwafers awaiting processing and wafers which have been processed. Thusthe interface section constructed as shown in FIG. 1 functions as bothan input subassembly, output subassembly and wafer holding station.

Interface 43 is substantially enclosed by the enclosure envelope 45.Interface 43 has open work space portions connected to the portions ofwork space 46 contained within the processing section 44. The interfaceincludes a interface port 56 formed through envelope 45. Interface port56 allows wafers to be loaded into and removed from processor 40.Interface port 56 is preferably provided with an interface port closurein the form of a movable door 59. Movable door 59 is powered and extendsupwardly from below to close the port and is retracted downwardly toopen the port. This construction allows the interface port door to beautomatically controlled to the extent desired.

FIGS. 6-12 show the principal operational portions of interface 43.These portions serve to provide a wafer transfer which transfers wafersfrom the industry standard wafer carriers 51 and installs the wafersonto the novel wafer trays 60. Additionally, interface 43 serves to holdwafer batches loaded onto the trays. These loaded tray batches are heldfor processing in the processor. Still further interface 43 allows forthe storage of unloaded wafer trays. As shown, interface 43 alsoperforms loading and unloading operations through interface port 56.

FIG. 6 shows that the preferred interface 43 has a base 99 which issecured to frame 41. A first or lower carriage 100 is mounted formovements, such as the preferred horizontal movement. A second or uppercarriage 102 is also mounted for horizontal movement. Interface 43 alsohas four elevators 104 which provide vertical movement.

Base 99 in some respects acts as an extension of frame 41 and furtherserves to separate the interface section compartment into an interfacesection portion of working space 46 and a mechanical compartment 98(FIG. 1) which is below and subjacent to the working space and base 99.As shown, base 99 is provided with four elevator openings 102 whichserve as apertures through which elevators 104 extend.

Base 99 also is provided with first carriage travel openings or clefts106. Clefts 106 receive portions of a first carriage support pedestal107 which extend downwardly from the first carriage beneath base 99. Thepedestal extends down to a first carriage support track (not shown)which is below base 99 in the mechanical compartment 98. Pedestal 107 isconnected to a first carriage operator (not shown) which isadvantageously in the form of a rotatable linear screw drive operatorsimilar to the operator described below in connection with secondcarriage 102.

FIG. 6 also shows that interface 43 includes two carriages 100 and 102which are movable relative to elevators 104. Carriages 100 and 102 arepreferably mounted for simple linear motion relative to the elevators.However, alternative configurations and movement patterns may bepossible. Carriages 100 and 102 are independently operable or otherwisecontrollable to allow different relative horizontal positions andmovements of the first and second carriages.

As shown, first carriage 100 is positioned above base 99 and below thesecond carriage 102. This preferred configuration results in the firstcarriage functioning as a lower carriage, and the second carriagefunctioning as an upper carriage. Elevators 104 serve to move waferbatches between a first or upper carriage level associated with thefirst carriage and a second or lower carriage level associated with thesecond carriage.

First carriage 100 includes an outer or forward portion forming a firstsection 111 of the carriage. This outward section is in the form of acantilevered shelf or carrier support projection 101. Carrier supportprojection 101 serves to support wafer carriers 51 thereon. Firstcarriage 100 is laterally movable to extend the carrier projection oroverhang through interface port 56 into the fully extended firstcarriage receiving position illustrated in FIG. 1. The overhangingcarriage shelf 101 is provided with carrier support features which areadvantageously in the form of carriage support ledges 109. The carriersupport ledges are preferably recessed areas formed in the upper surfaceof shelf 101. The carrier support features are advantageouslyconstructed to provide lateral support against unintended horizontaldisplacement in either X or Y directions (see FIG. 1). The carriersupport features also hold the carriers to prevent downward movementfrom a desired vertical or Z position, but allow vertical movement abovethe shelf for easy installation and removal of the wafer carriers.

The carrier support ledges 109 or other carrier support features arepreferably positioned adjacent or about first carriage transfer openings110. The support ledges are most preferably peripheral recessed areasabout the opening 110. Openings 110 are provided to allow extension ofthe elevators 104 therethrough. Extension of the elevators throughopenings 110 is used in conjunction with the transfer of wafers betweenthe wafer carriers 51 and wafer trays 60 in either incoming or outgoingdirections.

First carriage 100 also preferably includes a second or central section112 which includes a group of four first carriage pass-through openings113. Pass-through openings 113 extend through the deck of the firstcarriage to allow extension of the elevators therethrough. Pass-throughopenings 113 also allow unloaded wafer trays 60 to be passed upwardlyand downwardly through the first carriage deck in a manner as explainedmore fully below.

First carriage 100 is further provided with a third or rearward section113. Rearward section 113 includes an empty or unloaded wafer traymagazine or storage 115. The empty wafer tray storage is advantageouslyin the form of four arrays each having three receptacles to receivethree wafer trays therein. The receptacles each include shoulder pairswhich function as rests upon which the side rails 76 of the wafer traysrest. The shoulder pairs are along arranged along opposing sides of anempty tray gallery 116 which is common to all three receptacles of asingle storage array 115. Galleries 116 allow the heads of the elevatorsto extend upwardly to engage empty wafer trays and lift them for removalfrom the storage array. The empty tray gallery also extends through thedeck of the first carriage, and is contiguous with and open to theadjoining pass-through openings 114.

The empty tray storage is also preferably provided with an empty traystorage roof panel 117 which extends over and protects the empty wafertrays from downwardly drifting contaminating particles. The roof panelsare supported by first carriage rear section support panels 118.

The first carriage is further advantageously provided with a secondcarriage pedestal inlet opening 119 which allows a support pedestal ofthe second carriage to extend thereinto when the second carriage ismoved forwardly.

Interface 43 also includes the second or upper carriage 102. Uppercarriage 102 has an upper carriage deck 121 which is supported by asecond carriage support pedestal 122. Pedestal 122 has a linear driveoperator 123 which is advantageously in the form of a rotatable screwdrive 124 which moves the second carriage forwardly and backwardlybetween retracted and extended positions.

The upper carriage is provided to function as a loaded tray holding orinventorying station. As shown, this function is accomplished by havingthe second carriage in a position above the first carriage, and providedwith a series of loaded tray holders 125. Loaded tray holders 125 areformed as receptacle ledges formed in the deck. The receptacle ledgesare adjacent to second carriage elevator openings 126. Openings 126 arepreferably portal openings which have open entrances at the forward endsthereof. As shown, the upper carriage is configured to hold two groups,each group having four wafer trays in a four by two loaded wafer traystorage array.

Interface 43 also includes elevators 104 which have elevator rods orshafts 128 and enlarged elevator heads 129. The elevator heads areconstructed to engage the lower surface 62 of wafer trays 60 in a stablemanner. Most preferably the upper contacting face of elevator head 129is provided with four engagement projections 130 at the front and backof the contacting face. The engagement projections are spaced and sizedto fit within the longitudinal recesses 77 of trays 60 adjacent the endpanels. This provides positive engagement against lateral displacementof the trays relative to the elevator head during automated handling ofthe wafer trays by the interface.

Interface 43 is advantageously constructed to handle wafer carriers andwafer trays in groups or gangs of four at a time. Although thisconfiguration is preferred, it is alternatively possible to have othergang sizes.

Operation of Interface Section

The operation of interface 43 will now be described in connection withthe series of drawings shown in FIGS. 7-12. FIG. 7 shows the interfacemoved from the fully retracted positions of FIG. 6 into an initialloading position wherein the first carriage has been extended fully toposition the overhanging carrier shelf 101 through the interface port56. FIG. 7 also shows the carrier shelf loaded with four wafer carriers51 containing wafers 50. The carriers and wafers are positioned in thecarrier support receptacle ledges 109 over the wafer transfer openings110. The second carriage 102 is maintained in the fully retractedposition.

After the wafer carriers have been loaded onto shelf 101, the firstcarriage is retracted. When sufficiently retracted, the interface portdoor 59 is closed by extending the door upwardly. The first carriagecontinues to retract rearwardly until the elevator head 129 is alignedwith the stored trays held in empty wafer tray storage arrays 115. Atthis tray pick position, the first carriage is stopped and the elevatorsare aligned below the stored wafer trays. The elevators are thenextended upwardly to engage and lift the lowest empty trays from thefour storage arrays. The elevators are then stopped and held at a traylift elevation position.

The first carriage is then retracted further to bring the pass-throughopenings 114 into alignment with the elevators and elevated empty wafertrays positioned upon the heads of the elevators. At this pass-throughposition of the first carriage, the first carriage is stopped. Theelevators 104 are then retracted downwardly to pass the empty wafertrays through the deck of the first carriage. The empty trays are moveddownwardly until they are below and clear of the first carriage.

The first carriage is then moved rearwardly from the pass-throughposition into a transfer position. In the transfer position the firstcarriage is positioned so that the elevators and empty wafer trays heldthereon are aligned with the bottom opening of the wafer carriers heldin carrier holders 109. FIG. 9 shows the first carriage in the firstcarriage transfer position.

FIG. 9 further illustrates the transfer of wafers from the wafercarriers 51 and their installation onto the wafer trays 60. In FIG. 9the elevators have been extended upwardly after the first carriage hasassumed the transfer position. The transfer includes aligning theindividual wafer receivers 66 below the wafers 50 held in carriers 51.As the elevators extend upwardly, the tray moves up, into and throughthe open bottom of carriers 51. The edges of the wafers 50 are guided bythe V-shaped receiver mouths having downwardly converging receiver sidesurfaces 67. The edges of wafers 50 are guided by the receiver mouthsinto the relatively close fitting receiver slots or channels 68. Theedges of the wafers bear against the wafer slot bottom surfaces 69. Thebearing allows the wafers to further be lifted upwardly by the elevatingtrays 60.

FIG. 9 shows the elevators fully extended with trays 60 fully elevatedand with wafers 50 held in an aligned side-by-side array upon the trays.In this condition, interface 43 has transferred the wafers and theloaded wafer trays are ready to be moved to the holding stations onsecond carriage 102. To accomplish this, the second carriage is extendedoutwardly and forwardly from the retracted position into an extendedposition, such as the fully extended position shown in FIG. 10. In thisposition the second carriage has been moved forwardly so as to align therearward gang of loaded tray holding receptacles 125 with the elevatedwafer trays. The elevators are then retracted downwardly to lower theloaded wafer trays into the receptacles 125. After the loaded trays havebeen received in receptacles 125, the second carriage can then beretracted rearwardly into a retracted holding position, such as shown inFIG. 11. FIG. 11 also shows the elevators 104 fully retracted and thefirst carriage retracted with empty wafer carriers 51 awaiting dischargefrom the interface section.

FIG. 12 shows the first carriage repositioned into a fully extendedcarrier unload position. This position is also the initial load positionshown in FIG. 7. The empty wafer carriers are removed using a suitablemeans, such as manual removal by a human operator (not shown). Loadedwafer are then loaded onto the overhanging shelf of the first carriageand the process illustrated by FIGS. 7-12 is repeated for a second gangor group of carriers, wafers and trays. The second loading processdiffers only slightly from the process described above. One differenceis that different trays are used from the empty tray storage magazines115. Another difference is that the second gang of loaded trays are heldin the outer or forward holding receptacles 125 instead of the rearwardtray holders used by the first gang of wafer trays.

Processing Section

The processing section 44 of processor 40 will now be described ingreater detail. As shown, processing section 44 includes threecentrifugal processing stations 71-73. Each processing station includesa processing chamber bowl 131 which substantially encloses an internalprocessing chamber 132. A centrifugal processing enclosure door 134 ismounted for controlled powered vertical motion between a closed upwardposition and a downwardly retracted open position. Preferred doorconstructions are shown in U.S. Pat. No. 5,302,120, which is herebyincorporated by reference.

Within each processing chamber is a suitable rotor for receiving loadedwafer trays, such as rotor 133 detailed in FIG. 31. FIG. 32 shows afront view of rotor 133 without a wafer tray loaded therein. FIG. 33shows a front view similar to FIG. 32 with a loaded wafer traypositioned within the rotor. Rotor 133 is specially constructed toreceive and appropriately engage wafer tray 60 using wafer trayengagement features as explained below. The resulting interlockinginterengagement of the tray with the rotor substantially preventsdislodgement until appropriately removed.

Rotor 133 includes three principal ring pieces 141-143. The front ring141 has a beveled rotor opening 149. The front, central and rear ringsare connected by connecting longitudinal bars 144 and 145. Upperlongitudinal bars 144 are spaced from the wafer trays 60 and areprovided with inwardly directed longitudinal bumpers 146. Adjacent thewafer tray receptacle 136 are three additional longitudinal bars 145.The inward edges of bars 145 serve to guide and support wafer trays 60appropriately positioned within the wafer tray receptacle.

The wafer tray engagement features used in the wafer tray receptacleinclude a rotor tray receiving channel 136. The sides of receivingchannel 136 include rotor tray engagement projections 137. The rotortray engagement projections are shaped and sized to complement and bereceived along the tray side channels 81. However, the tray sidechannels are substantially higher than the engagement projects becausethe trays are loaded using a tray engagement tool 180 which insertsbetween the downward facing bearing surface 82 of the tray and theupward surface of rotor engagement projections 137. Additionally, theclearance is preferably sufficient so that engagement tines 184 can alsopass through the available space during insertion into the rotor toretrieve a tray therefrom.

The wafer tray engagement features used in rotor tray receiving channel136 also include opposing side receiving flutes 138. Flutes 138 receivethe longitudinal side flanges 85 of tray 60 in relatively close fittinginterengaging relationship. The bottom or foot surface 86 of tray 60bears upon inwardly directed tray support surfaces 147 on thelongitudinal bars 145. This advantageously occurs between both outersupport bars 145 with both side rails 76 of the tray, and along acentral tray support bar 145 and the center longitudinal foundation bar75 of the tray. Central longitudinal bar 145 is advantageously providedwith a bumper bar 148 (FIG. 32).

The processing stations are each independently driven by rotatingassembly motors 153 and have other features of a centrifugal fluidprocessor as needed for the desired processing of that station.Additional details of a preferred construction of centrifugal processorare well-known or can be taken from the attached Appendix hereto.

The specific processing performed in processing stations 71-73 can eachbe different or of similar nature. Various liquid and gaseous processingsteps can be used in various sequences. The processor is particularlyadvantageous in allowing a series of complex processes to be runserially in different processing chambers set up for very differentchemical processing solutions. All the processing can be accomplishedwithout human handling and in a highly controlled working space, thusreducing contamination and human operator handling time.

The processing section 44 also includes a processing section portion ofworking space 46. This portion of the working space is frontward ofprocessing stations 71-73 within the enclosure envelope 45. Thisprocessing section working space allows the tray conveyor describedbelow to supply and remove loaded wafer trays to and from the processingstations.

Conveyor

Processor 40 is advantageously provided with a mechanical wafer trayconveyor 140. Conveyor 140 will be described initially with reference toFIGS. 13 and 14. The preferred conveyor includes a conveyor carriage ortram 156 and a mechanical arm assembly 157 which is mounted on the tram.The tram moves the mechanical arm assembly along a defined tram travelpath. The mechanical arm assembly moves the wafer trays 60 upwardly,downwardly, inwardly, outwardly, and adjusts the tilt within a range ofavailable positions and orientations.

Tram 156 has a base 160 which connects with a base subassembly 165 whichforms part of the mechanical arm assembly (see FIG. 35). Thecomplementary base parts 160 and 165 join to provide a combined baseassembly which serves as a movable base for the mechanical arm assembly.

Tram 156 moves along a guide track which defines the tram path alongwhich the tram travels. The guide track is advantageously formed byupper and lower guide bars 158 and 159 which are mounted along theoutward side of a track support member 161 forming part of the frame.This construction allows the mechanical arm assembly to extend intocantilevered positions to reach processing stations 71-73 with goodpositional stability. The guide bars are engaged by track followers inthe form of linear bearings 171 which are secured to the inward face ofthe tram base 160. The linear bearings 171 are advantageously providedwith rod engaging rollers spaced at equal 120° arc positions about theguide bars 158 and 159.

The tram is powered along the defined path guide track by a suitabletram driver, such as a track magnetic drive in the form of linearmagnetic motor 163. Linear magnetic motor 163 is most preferably alinear brushless direct current motor. Such a preferred tram driver usesa series of angled magnetic segments which magnetically interact with anelectromagnet on the base of the robotic conveyor to propel the tram andattached mechanical arm up and down the defined path track.

The path position of the base 160 along the guide track is preciselycontrolled using a positional indicating array (not shown) affixed tothe front of the track support member adjacent to guide bars 158 and159. An optical emitter detector pair (not shown) are mounted upon basepiece 160. The optical emitter detector pair serves as a track positionsensor or indicator which reads the position of the tram base from theindicating array after proper calibration. The positional accuracy ofthe track position indicator is preferably in the range less than 0.003inch (approximately less than 0.1 millimeter).

FIG. 35 shows the mechanical arm assembly 157 in a simplified form forpurposes of illustrating and introducing the preferred construction.Mechanical arm assembly 157 is preferably of a type which can providehighly accurate positional stability and repeatability for precisecontrol and movement of the loaded wafer trays which are supported atthe distal end of the mechanical arm. As shown, mechanical arm assembly157 includes a base portion 165 which is secured to tram base piece 160.An upper arm assembly having two complementary upper arms 166 aremounted to pivot relative to the body portion 165. Upper arms 166 arepreferably connected together so as to provide coincident angularmovement using an upper arm connection member, such as torque tube 167.The upper arm assembly pivots with respect to the base about a shoulderpivot axis 168.

A forearm assembly is connected near the outer distal end of the upperarm assembly. The forearm assembly advantageously includes two forearms172 which are joined by a forearm connection member 174. The forearmassembly also uses opposing face panels 173 (FIG. 15) to provide astrong and mechanically integrated forearm assembly which is resistantto twisting and provides a high degree of positional stability. Theforearm assembly is connected to the upper arm assembly to allowrelative pivotal movement about an elbow pivot axis 169.

The distal end portions of the forearm assembly support a hand assembly176. Hand assembly 176 is supported in a manner allowing pivotalmovement about a wrist pivot axis 170. The hand assembly includes twocomplementary hand bars 177. Hand bars 177 are joined together by a handcross piece 178. The hand assembly also preferably includes a trayengagement tool 180 which is mounted to the hand cross piece 178.

FIGS. 29, 30 and 35 show that the preferred tray engagement tool 180includes a complementary pair of hand extensions 181. Hand extensions181 are advantageously semi-cylindrical sections which form a cradlewhich engages the wafer tray 60. The hand extensions preferably engagethe wafer tray along the side rails, such as along the outer sidesurfaces of the tray. More specifically, the hand extensions preferablyare spaced to define a hand extension gap 182 having parallel insideengagement edges 183. Tool engagement edges 183 are received along thewafer tray side channels 81. The tool engagement edges are slidlongitudinally along side channels 81 to position the tool forengagement with the wafer tray.

The ends of the hand extensions are preferably provided with end tines184. When the hand extensions are lifted upwardly, the engagement edgesbear upon the downward facing bearing surface 82 of the wafer sidechannels. Simultaneously therewith, tines 184 move upwardly to latch atthe end of the wafer tray to prevent longitudinal slippage of the wafertray upon the hand extensions. This latching places the tines along endsurfaces of the wafer tray. The hand extensions can advantageously beprovided with perforations 185 (partially shown in phantom in FIG. 35)to lighten the weight of the assembly.

The preferred construction of mechanical arm assembly 157 will now bedescribed in greater detail with reference to FIGS. 16-28 in addition toother Figs. of this application. FIG. 16 shows the mechanical armassembly connected to tram base 160 using base pieces 165. A shoulderjoint cover 313 is shown installed in FIG. 16. Similarly, an elbow jointcover 187 is shown installed about components of the elbow joint. Mostof the hand assembly 176 is not included in FIG. 16 to simplify thedrawing. FIG. 17 is similar to FIG. 16 except it shows how themechanical arm 157 has been subdivided to allow enlargement andillustration of various details of the preferred construction. Thedetailed illustrations are sectional views presented in FIGS. 18-28.

FIGS. 18 and 19 show components associated with the wrist jointconnection between the hand assembly and the forearm assembly. Thepreferred wrist joint construction includes two hand connection hubs 190which pivot to provide tilting action of the hand assembly. Hubs 190 areeither integrally connected to the hand bars 177 (as shown), ordetachably connected thereto. Hubs 190 are pivotally supported relativeto the forearm members 172 using hand hub support bearings 191. Bearings191 are supported by forearms 172 against radial movement, and againstlongitudinal movement by capture between an outboard seal housing 192and an inboard bearing mounting ring 193. Fasteners 194 extend throughring 193, forearm 172, and into seal housing 192. Seal housing 192 holdsa hub shaft seal 195.

Hubs 190 are limited within a defined range of angular motion using awrist hub angular displacement limiter. The angular displacement limiteris advantageously in the form of an axial pin 197 which fits within apin socket 198 formed in the hub 190. Pin 197 extends into an annularslot 199 formed in the outer face of the seal housing 192. The angularslot advantageously allows a range of motion of approximately 100°-120°of arc.

The first hub 190 shown in FIG. 18 is connected to rotate with a handdrive pulley 200 using a shaft key 201 supported in associated keywaysformed in the hub and pulley. A spacer ring 204 is between the innerrace of bearing 191 and pulley 200. A pulley retainer 202 is fastened tothe inboard end of the hub using a fastener 203 to keep the pulleyagainst axial movement.

Pulley 200 has cable receiving grooves 205 formed in the periphery ofthe pulley. Hand drive cables 206 are received within the grooves 205.Pulley 200 is advantageously provided with a cable clamping block 207which is set in the pulley within a recess. The cable clamping block hasa clamp head 208 which squeezes down upon cables 206 when fasteners 209are tightened.

Because of the need for highly accurate and repeatable positioning ofthe hand assembly, it has further been found desirable to provideindependent bearing support for pulley 200. This can be accomplishedusing a pulley bearing 210. Pulley bearing 210 is supported by anintermediate spacer bar 211 which extends between the wrist joint andthe elbow joint.

The pulley retainer 202 is advantageously formed with a pair of annularfins 213 and 214. Annular fin 213 can be moved into a position withindetector gap 215 of optical detector 216. Similarly, annular fin 214 canbe moved into a position within detector gap 217 of optical detector218. The optical detectors are mounted to the forearm cross member 174.Optical detectors 216 and 218 sense the outer bounds of desired angulartravel of the hand assembly and serve effectively as limit switchesproviding signals to the controller operating the mechanical arm.

FIG. 19 shows that the second hub 190 is connected to an angularposition encoder 220 which is mounted to cross member 174 using anencoder mount 221. The shaft of the position encoder is coupled to hub190 using a bellows shaft coupling 222. Movements of the hand assemblyrelative to forearms 172 are detected with greater precision by encoder220. A preferred encoder discriminates a 360° circle into approximately64,000 divisions.

FIGS. 22 and 23 show the elbow joint between forearms 172 and upper arms166. The elbow joint pivots about elbow joint axis 169. Pivotal actionbetween the upper arm assembly and forearm assembly is accommodated bytwo main elbow pivot bearings 225 and 226. First main elbow pivotbearing 225 is preferably a cross roller thrust bearing. Second mainelbow pivot bearing 226 is preferably a ball bearing. The outer race offirst main bearing 225 is connected to the upper arm 166 using a bearingsupport ring 227 and fasteners 228 which extend through apertures inupper arm 166. A similarly functioning bearing support ring 229 andfasteners 230 are used in connecting second bearing 226 to upper arm166.

Bearing 225 receives within its inner race a forearm mounting tube 233.Forearm 172 is secured to mounting tube 233 using fasteners 234. Aproximate forearm cross brace 235 extends between and is connected toforearms 172 using fasteners 236. Mounting tube 233 is used to pivotallysupport a cable drive transfer shaft 240. Cable drive transfer shaft 240is supported within mounting tube 233 using a pair of transfer shaftbearings 238. A tubular bearing spacer 239 extends between the innerraces. Bearing retainer rings 241 and 242 are fastened to hold thebearings axially against the mounting tube 233.

The inboard end of transfer shaft 240 is advantageously formed as anelbow joint transfer pulley 243. Elbow joint transfer pulley 243 hasparallel cable receiving grooves 244 and a cable mounting block 248similar to wrist joint pulley 200. The cable mounting block 248 has acable mount head 249 fastened to the pulley to secure cables 206. Cables206 extend between pulleys 243 and 200 to effect movement of pulley 200and the hand assembly.

Inboard transfer pulley 243 is driven by an outboard transfer pulley250. Pulley 250 is fastened to transfer shaft 240 using fasteners 251.Cables 252 are looped around pulley 250 and hand drive transmissionoutput pulley 255 at the shoulder pivot (see FIG. 26). Pulley 255 isdriven by a hand drive electrical motor 256. The output of motor 256 iscoupled to pulley 255 via a harmonic drive speed reduction transmission257. The frame of motor 256 is held securely to the base 165 of themechanical arm. The reduced speed output from the harmonic drivecontrols the tilt of the hand assembly. This construction allows thetilt of hand assembly 176 to stay at a fixed attitude even though theupper and lower arms pivot. Thus the attitude of the hand assembly onlychanges when the hand drive motor 256 is controlled to drive.

FIGS. 22 and 23 also show an elbow joint encoder 260. The casing of theencoder is mounted to the forearm assembly cross member 235 using anencoder mount 261. Encoder mount 261 includes an isolation mount band262 to reduce vibratory transmission to the encoder. The shaft of theencoder is connected through a bellows coupling 263 to an upper armencoder coupling shaft 264. The outboard end of shaft 264 is fixed tothe upper arm 166 using a coupling shaft mount 265. Relative angularmotion between the upper arm and the forearm is detected as relativeangular motion between the encoder case and encoder shaft. Thisinformation is provided to the controller used to control mechanical arm157. A partition plate 279 extends from mount 265 to help guide wiring(not shown).

Between encoder coupling shaft 264 and the tubular transfer shaft 240 isan assembly advantageously used to guide electrical wires. The transfertube wire guide includes an inboard part 266, an outboard part 267, andan intermediate tubular member 268. Inboard and outboard parts 266 and267 have passageway apertures 269 through which wires are run.

FIG. 23 shows the forearm drive assembly 270. Drive assembly 270includes a forearm drive motor 271 and a forearm drive speed reductiontransmission 272. The outer housing of motor 271 is coupled to theforearm assembly. The shaft of motor 271 is connected to thetransmission 272 which is preferably a harmonic drive providing 160:1gear reduction. The third connection of the harmonic drive is coupled tothe upper arm assembly via a harmonic drive coupling plate 273 usingfasteners 274. The opposite, inboard, end of motor 271 is provided witha motor encoder 276 which indicates operation of the forearm motor 271and provides a signal indicative thereof. A thumb wheel 277 is alsoadvantageous provided to allow manual movement of the motor duringmaintenance and setup.

The elbow joint is also advantageously provided with an elbow jointlimit switch 278 which is tripped when the relative position of theforearm reaches the limits of desired angular travel.

FIGS. 26-28 show the shoulder joint which pivots about pivot axis 168.The shoulder joint provides for relative pivotal motion between the basepieces 165 and the upper arm assembly. Base pieces 165 are secured totram carriage 160. Relative angular movement between base pieces 165 andthe upper arms 166 is supported by main shoulder pivot bearings 281 and282. First main bearing 281 is advantageously a cross roller thrustbearing. Second main bearing 282 is advantageously a ball bearing.

The outer race of bearing 281 is secured to the base piece 165 using abearing retainer 283 which is fastened to base 165. The inner race ofbearing 281 is coupled to an upper arm coupling ring 285. Coupling ring285 is secured to the upper arm 166 using fasteners 286. A seal 287 isadvantageous positioned between bearing retainer 283 and coupling ring285. An inner race bearing retainer ring 288 is fastened to couplingring using fasteners (not shown).

The housing of the hand drive motor 256 is mounted to the base piece 165using bolts 290. The shaft 291 of motor 256 is connected to the harmonicdrive transmission 257. The casing of the harmonic drive is capturedbetween a pulley mounting ring 292 and the housing of motor 256. Thisfixes the position of the harmonic drive casing. The third or outputconnection of the harmonic drive is connected to a pulley drive piece294 using fasteners 295. The pulley drive piece transmits torque fromthe output of the harmonic drive to hand motor pulley 255.

Pulley 255 is supported for pivotal movement upon mounting ring 292using bearings 296. Bearing 296 are held in axial position by a bearingretainer 297 fastened to mounting ring 292 by fasteners (not shown). Theinboard end of motor shaft 291 is advantageously fitted with a thumbwheel 298 for manual manipulation of the motor during setup andmaintenance. A motor encoder 299 is connected with motor 256 to providemotor response information to the mechanical arm controller which isused along with information from the hand angular position encoder 220to provide precise control of the mechanical arm assembly.

FIGS. 27 and 28 show the drive used to move the upper arm assemblyrelative to base pieces 165. The upper arm assembly drive includes anupper arm drive motor 301. Motor 301 has a shaft 302 which drives aharmonic drive speed reduction transmission 304. The casing of theharmonic drive is coupled securely to the housing of motor 301, both ofwhich are secured to base pieces 165. The flexible spline or thirdoutput 303 of the harmonic drive is coupled to an upper arm drive piece305 using fasteners 306. Drive piece 305 is connected to an upper armbearing ring 307 which is held by the second main bearing 282. Thisallows the bearing ring 307 and attached upper arm pieces to pivot.Seals 310 and 311 are advantageously included to seal the enclosed motorand transmission space to reduce contamination within the working spaceof the processor.

The inboard end of motor 301 is provided with a motor encoder 315 and athumb wheel 316. An upper arm drive position encoder 320 is mounted withan isolation connector 321 to a support or mount 322 which is connectedto base ring 165. The shaft of the encoder is connected by a clamp 389to an arm 388. Arm 388 connects to piece 307 to indicate angularmovement of the upper arm. A limit switch 325 is positioned to trip whenthe upper arm assembly extends to the limits of its desired angulartravel range.

Upper arms 166 are also preferably provided with outer cover pieces 312to enclose components of the upper arm assembly. The base is providedwith a base cover cylinder 313 to partially confine and facilitateenclosing the internal space which holds includes the motors andtransmissions.

Control System

FIG. 34 shows a preferred control system used in processor 40. Thecontrol system advantageously uses a modular design which incorporatecommercially available computer modules, such as 80486 based computers,to perform various functions. FIG. 34 shows the human operatorinteraction stations 331 and 332. The first station 331 has a computerprocessor 341 of conventional design and an electrically attacheddisplay and control panel 57. Control and display panel 57 is accessiblefrom the front or clean room side of processor 40. The second controlstation. 332 has a computer processor 342 also of conventional designand an electrically attached display and control panel 343 which isavailable for operation on the gray room or back side of processor 40.Both control stations are connected using a standard network interfacehub 350. Network hub 350 is connected to a central controller, such as acomputer file server 351. Hub 350 can also be used to connect an outsidecontrol or monitoring station 360 for additional control capabilities,data acquisition, or monitoring of processing and control functions.

Hub 350 is further connected to processor control modules 361-363, whichare also conventional computers without displays. Processor stationcontrol modules 361-363 are each associated with processing stations71-73 respectively. These station control modules allow independentprocessing routines to be run at the processing stations and for data tobe recorded indicating the processing performed in each particular batchbeing run by each processing station.

Processing station control modules are connected to and interact withthe processing station motors, plumbing, etc which are collectivelyidentified with the processing station number 71-73 in FIG. 34.

FIG. 34 further shows an interface subsystem controller 381, which againis a computer. Interface subsystem controller 381 is electricallyconnected to various features of the interface subsystem to both controloperation and receive confirmatory signals of movements and positions.The interface controller 381 is preferably connected to the interfacesection to receive signals through a number of optical fibers 386 usedto convey signals from positional encoders for the first and secondcarriages 382, limit switches 383 which detect the limit of travel ofthe carriages and elevators, and wafer detectors 384 which detect wafertrays and wafer carriages held in the interface section. The system ispreferably constructed so that most or all sensed signals used in thecontrol and operation of the interface are communicated by optical fiberto eliminate the risk of cross talk between signal lines. The opticalfiber transmitted signals are converted into electronic signals by anoptical fiber signal converter 387 which produces electronic signalswhich are communicated to computer 381.

FIG. 34 still further shows a conveyor control module in the form of acomputer 391 without display which is electrically connected to variousparts of the conveyor, such as the mechanical arm motors 256, 271 and301, encoder 220, and other components thereof not specificallyillustrated.

The conveyor control module also preferably receives a number of signalsthrough optical fibers 396. Optical fibers 396 are used to conveysignals from angular position encoders and motor encoders for theconveyor 140 which are for simplicity exemplified by encoder 220 in FIG.34. Limit switches for the conveyor are exemplified by limit switch 278in FIG. 34. Hall effect sensors 395 are used in sensing operation of themotors of the conveyor. The system is preferably constructed so that allsensed signals used in the control and operation of the conveyor arecommunicated by optical fiber to eliminate the risk of cross talkbetween signal lines and provide a smaller cable bundle which is movedin connection with tram motion up and down the track. The optical fibertransmitted signals are converted into electronic signals by an opticalfiber signal converter 397 which is connected to reconvey the signals tocomputer 391.

Alternative Configurations

FIG. 36 shows an alternative configuration of processor 400 constructedand capable of operation according to this invention. Processor 400includes two interface sections 401 and 402, which are advantageouslymounted upon opposing ends of the processing system. Interface sections401 and 402 are substantially or identically the same as interfacesection 43 described above. Between the interface sections are a seriesof processing stations 411-415. Stations 411-413 and 415 are similar tocentrifugal processing stations 71-73. Processing station 414 is of analternative design which will be more fully described below. Otheralternative constructions are also possible.

Processor 400 has a processing enclosure 430 which in part defines aninterior working space 431 adjacent to the processing stations andincluding the interface spaces accessible to the wafers being processed.

Processor 400 can be operated to load wafer carriers at first interfacestation 401 and remove processed wafers in wafer carriers at secondinterface station 402. Alternatively, each interface station can bothload and return processed wafers through their associated interfaceports.

The alternative wafer submersion processing station 414 is shown ingreater detail in FIGS. 37-39. Submersion or immersion processingstation 414 includes two processing bath or immersion tanks 501 and 502which are in front and back, respectively. Tanks 501 and 502 are used tohold processing liquids, such as acids and water. Tanks 501 and 502advantageously have enlarged brims 513. Station 414 includes a frameextension 505 which is a vertical member which mounts a wafer traydipping mechanism or dipper 507.

Dipper 507 includes a movable dipper arm 508 which moves within achannel 504 using a dipper drive (not shown). The dipper drive ispreferably an X-Y (two-dimensional) electrical servo-motor poweredpositioning drive. Alternatively, two linear electrical servo-motorpowered drives can be coupled in a perpendicular configuration to allowthe horizontal and vertical motion needed to traverse the channel 504.The dipper drive is advantageously enclosed within frame extension 505.

The dipper mechanism also preferably includes a dip head 509 which, asshown, is suspended from dipper arm 508. Dip head 509 advantageouslyincludes a dip head connector 512 which is connected to the dipper arm508. The dip head connector is also connected to a longitudinal topmember 522. Longitudinal member 522 forms part of a dipping mechanismtray holder 514.

The dipping mechanism tray holder 514 also preferably has a basket whichis open, perforated or otherwise foraminous in construction so as toallow liquid movement about the wafers 50 being processed. As shown thebasket includes a series of circumferential rings 521. Rings 521 areconnected by a top bar 522 which is suspended from connector 512. Thelower portions of the rings are connected by lower longitudinal members523 and a basket bottom piece 524 which is preferably perforated. Thelower longitudinal members and bottom piece are preferably formed andspaced to provide a tray receptacle for receiving and holding wafer tray60. The tray receptacle is similar in design to the constructionemployed in rotor 133, and the description will not be repeated. Thetrays are slid into and retrieved from the tray holder using themechanical arm.

Dipper 507 is shown in FIG. 37 with the movable subassembly of thedipper in a fully downward or submerged position in solid lines. In thissubmerged position the wafers held in the wafer tray and tray holder arecapable of full insertion into tanks 501 or 502 to provide fullimmersion or submersion in a bath of processing fluid (not shown). FIG.37 also shows in phantom lines the dipper movable assembly positioned inan upward retracted position. Partial immersion positions exist betweena fully upward retracted position and the downward submersion positionshown for rear tank 502 in FIG. 37.

In operation, wafers held upon trays 60 are inserted into the dipperbasket and the mechanical arm tray holder is then retracted. The dipperarm is then moved into the desired position to achieve immersion of atleast part, or more preferably full submersion, of the wafers and trayinto the desired processing bath contained in either tank 501 or 502.The dipper driver can be controlled to jog the wafers eitherhorizontally or vertically and provide agitation of the wafers withinthe bath of processing fluid. The wafers are left in the desiredimmersion position until the desired processing has been accomplished.The wafers and associated tray are then moved by the dipper arm into anupward position wherein the processing chemical can drain back to thetank. Thereafter the movable dipper assembly is either held for removalof the wafers and trays, or moved into the second tank 501 or 502, asdesired. The wafers are then processed in the second processing fluiduntil the desired processing has been completed. Thereafter the dipperarm is moved upwardly to withdraw the wafers from the processing bathand preferably left to drain briefly to conserve processing fluids. Thewafer trays are then retrieved by the mechanical arm in a manner similarto that described above in connection with the retrieval of trays fromrotor 133.

Operation and Methods

The operation and methodology of processor 40 has in part been explainedabove. Further description will now be given.

The invention further includes novel methods for processingsemiconductor wafers and similar units requiring extremely lowcontamination. The methods can include providing a suitable processor,such as processor 40 described hereinabove and the associated subsystemsthereof. Novel methods of processing such units preferably are performedby loading the wafers or other units to the system in carriers, such aswafer carriers 51. Such loading step is to a work space which isenclosed or substantially enclosed, such as working space 46. Theloading step can include opening an enclosure door, such as door 59 ofthe interface port to allow entry of the wafers. The loading preferablyis done by opening the enclosure door and extending a loading shelfthrough an open interface opening, such as port 56. Positioning of theloading shelf can be accomplished by moving the first carriage outwardlyinto an extended loading position.

The loading is further advantageously accomplished by depositing thewafers held within wafer carriers onto an extended loading shelf whichis positioned through the interface opening. The wafers held in thecarriers are positioned by depositing the loaded wafer carriers onto theextended shelf. The first carriage is thereafter moved such as byretracting the first carriage and the extended cantilevered shelf. Afterretracting the shelf through the interface port the methodsadvantageously include closing the interface port door or other similarenclosure door.

The methods also preferably include transferring wafers to a wafer tray,such as tray 60. Such transferring preferably is done by transferringthe wafer from a wafer carrier and simultaneously onto the wafer tray.This is done by lifting the wafers from the wafer carrier using thewafer tray. The transferring is advantageously accomplished by extendingthe wafer tray through an opening in the wafer carrier, for exampleelevating the wafer tray up through a bottom opening in the wafercarrier to lift the wafers. The transferring preferably is accomplishedusing an array of wafer receivers, such as receivers 66. The waferreceivers which receive the wafers are preferably spaced and parallel toallow the receivers of the tray to be extended to receive the wafers inan edgewise relationship. The receiving is most preferably done usingreceiving channels having converging side surfaces which perform aguiding function as the tray and wafers approach relative to oneanother. The receiving also advantageously includes positioning edges ofthe received wafers into receiver bottom sections 68 which includespositioning the edges into slots having spaced approximately parallelreceiving slots with surfaces along marginal edge portions which holdthe wafers in a spaced substantially parallel array.

The transferring also preferably includes extending, such as by lifting,the wafers received upon the wafer trays so as to clear the wafer freeof the wafer carriers. This clearing of the wafers installed upon thetrays completes the transferring of the wafers to perform an installingof the wafers onto the wafer trays.

The transferring and installing operations can in the preferredembodiment be preceded by storing wafer trays in a wafer tray storagearea or array. The wafer trays can be stored by slipping the wafer traysinto storage receptacles, such as upon storage support ledges 109. Thestoring can occur by vertically arraying the unloaded wafer trays.

The wafer trays held within the storage receptacles are also preferablyremoved by unloading therefrom. This unloading can advantageously bedone by elevating or otherwise by extending a tray support, such as head129 into proximity to and then engaging the head with the tray. Theextending can function by lifting the engaged head and then moving todislocate the lifted tray from the storage area. This dislocating canmost easily be accomplished by moving the storage area, such as bymoving the second carriage 102, most preferably by retracting thecarriage.

The steps preceding the transferring step can also advantageouslyinclude passing the engaged wafer tray through a pass-through opening inthe first carriage. The passing-through step can be accomplished bylowering or retracting the engaged wafer trays through the pass-throughopening and thus placing the wafer tray in a position suitable forperforming the transferring. The passing-through most preferablyincludes aligning the engaged wafer tray with the pass-through opening.

The steps preceding the transferring and installing process alsopreferably include relatively moving the engaged wafer trays relative tothe wafer carriers to bring the engaged wafer trays into alignedposition. This aligning step is most ideally done by retracting orotherwise moving the first carriage rearwardly until the wafer carrieropening and engaged wafer tray are aligned for transfer andinstallation.

After the transferring or other installing of the wafers onto the wafertrays, the loaded wafer trays are preferably inventoried, such as byholding upon the second carriage. This storing is in the preferredembodiments done by extending or otherwise moving the second carriage orother loaded tray storage relative to the loaded wafer trays. The loadedwafer trays can be stored by positioning them over a holding featuressuch as holding receptacles 125. The positioning can be followed bylowering the wafer trays into the holders and then supporting the wafertrays by the wafer holders.

The loaded wafer trays can then be processed further by loading thewafer tray onto a wafer conveyor, such as conveyor 140. The loading ontothe conveyor can be done by moving a wafer tray engagement tool intoengagement with the tray. This engaging step is most preferably done bysliding portions of the wafer engagement tool along receiving featuresof the wafer tray, such as by sliding the engagement edges 183 alongreceiving channels 83 of the tray, most preferably along opposing sidesof the wafer tray. The engaging can further be perfected by lifting orotherwise interengaging the wafer tray engagement tool with the wafertray being moved. This is most preferably done by lifting the toolrelative to the tray and thereby positioning a longitudinal engagementfeature, such as tines 184, against a complementary surface of the trayso that longitudinal or other lateral displacement of the tray upon thetool does not occur due to movement.

The methods also preferably include moving the wafer trays to one ormore processing stations. The moving can be done by tramming the loadedwafer tray along a defined guide track upon a movable tram. The movingor conveying step can also include horizontally positioning the wafertray, and vertically positioning the wafer tray, and orienting theangular orientation of the wafer tray to enable the wafer tray to bepositioned into a processing chamber. This functioning is preferablyfollowed by loading the wafer tray into the processing chamber. Thisloading can be done by inserting the loaded wafer tray into acentrifugal wafer tray rotor. The inserting or other loading step canbest be accomplished by sliding the loaded wafer tray into an engagedrelationship with the rotor by receiving interengaging parts of therotor and wafer tray.

The wafers which were inserted or otherwise installed into theprocessing chamber are then preferably further treated by processingwith fluid processing materials, such as chemical processing fluids,liquid or gas; or heating, cooling or drying fluids, most typicallygases.

The processing can also advantageous be centrifugal processing whichinvolves rotating or otherwise spinning the wafers being processed,particularly when still installed upon the wafer trays. The spinningpreferably occurs with the wafers positioned within a rotor whichperforms a restraining function keeping the wafers in an aligned arraycentered near the axis of rotation. The centrifugal processing caninclude a variety of spinning, spraying, rinsing and drying phases asdesired for the particular articles being processed. Additionalpreferred processing parameters are included in the appendix hereto.

The processing can also include immersion processing, such as can beperformed by the immersion processing station 414 described above.Immersion station 414 or other suitable station can perform processeswhich include positioning a dipper so as to allow installation of aloaded wafer tray thereon. As shown, this is down by raising the dipperarm upwardly and positioning the wafer holding basket with an open sideforwardly. The mechanical arm can then function by inserting orotherwise installing or loading the basket with an open receiver foraccepting the loaded wafer tray. After insertion and loading of thewafer tray onto the dipper movable assembly, then the dipper arm is usedby moving the held wafers on the trays so as to process the wafers inthe desired immersion tank. This dipping or immersing operation ispreferably a submersing step which places the entire tray of wafers intothe bath of processing chemical. Thereafter the wafers are processed byholding the wafers in the desired immersion position and conduction anymonitoring desired while performing the bath processing.

The immersion processing methods can further include withdrawing thebathed wafers, such as by lifting the dipping arm upwardly. The waferholding head is then preferably removed from the bath and is held in adraining condition to allow processing liquids to drain back into thebath from whence they were removed. The immersion processing can then berepeated for the second or other subsequent processing bath. After thebathing processes have been finished at any particular station then themechanical arm is used by unloading the wafer trays from the dippers andthe loaded wafer trays are moved to the next desired processing station.

The methods of this invention also include unloading the wafer traysfrom the processing stations, such as by engaging the loaded wafer trayswith a tray engagement tool in processes similar to those discussedabove. The engaged and loaded wafer tray is then preferably processed byrelocating the wafer tray to a second processing station, such as byconveying by moving with the mechanical arm assembly. The relocating caninclude withdrawing the wafer tray from the processing chamber andmoving to another processing chamber and installing the wafer traytherein. The processing can then be furthered using a processingsequence similar to that described or in other processing steps desired.

The wafer trays are also handled by conveying the wafer trays andsupported wafers to a holding station and holding the wafers thereat.The holding awaits an interface unloading sequence which can beaccomplished by transferring the wafer trays and supported wafers fromthe wafer trays back to wafer carriers. The transferring orretransferring step back to the wafer carriers is essentially a reverseof the transferring and installing steps described above. Suchadvantageously includes unloading the wafer trays from the holding area,such as by lifting loaded wafer trays from the holding receptacles. Thelifting or other removing of the wafer trays from the holders isadvantageously done by extending an elevator head through an alignedwafer carrier and elevating the wafer trays. The holders are then movedin a relative fashion from the lifted or otherwise supported wafertrays. This is advantageously done by moving the second wafer carriage,such as by retracting the wafer carriage rearwardly away from thesupported wafer trays. The relative moving of the removed loaded wafertrays and holders allows the wafer trays to be lowered or otherwiseretracted. The retracting is best performed by lowering the wafer traydownward after aligning the wafer tray with a wafer carrier. Thelowering causes a transferring of wafers from the wafer trays onto thewafer carrier.

The methods also preferably include retracting the elevators downwardlyand beneath the first carriage with the supported and now unloaded wafertrays thereon. The first carriage can then be moved into thepass-through position by aligning the empty wafer tray with thepass-through opening. The empty trays can then be extended, such asupwardly, through the pass-through opening.

The methods then preferably include moving the transferred wafers heldin the wafer carriers into an extended unloading position through theinterface port. This is advantageously done by moving the first carriageforwardly and extending the cantilevered shelf out through the interfaceport.

The moving of the first carriage forwardly to accomplish unloading, canalso be used to perform a storing function for the empty wafer traysinto the empty wafer storage array. This is preferably done by elevatingthe wafer trays into an aligned storage position, such as at a desiredaligned storage elevation and then moving the first carriage andattached storage gallery toward the engaged empty wafer tray. Onceinstalled the empty wafer tray can be lowered into a storage position.The empty wafer trays are preferably stored in a downwardly progressingfashion when the elevator is used.

The wafer carriers and associated processed wafers are taken from theprocessor by removing the loaded wafer carrier from the cantileveredshelf after such has been extended out through the interface port orother unloading passageway. This is typically done by manually graspingthe wafer carrier with the processed wafers therein.

In compliance with the statute, the invention has been described inlanguage more or less specific as to structural and methodical features.It is to be understood, however, that the invention is not limited tothe specific features shown and described, since the means hereindisclosed comprise preferred forms of putting the invention into effect.The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

We claim:
 1. A method for processing wafers, comprising:loading wafersheld in a wafer carrier into an enclosed work space; transferring wafersfrom said wafer carrier to a wafer tray to produce a loaded wafer trayhaving a plurality of wafers positioned thereon; said wafer trayproviding fluid access to surfaces of the wafers positioned thereon forprocessing; storing unloaded wafer trays upon a first carriage for usein said step of transferring wafers: moving the first carriage from acarrier load position wherein said wafer carrier loaded with wafers isloaded onto the first carriage, to a tray pick position: elevating astored unloaded wafer tray from the first carriage: moving the firstcarriage from the tray pick position to a transfer position wherein saidfirst carriage is ready for said step of transferring: conveying theloaded wafer tray to and between multiple processing units which haveaccess openings to said enclosed work space.
 2. A method for processingwafers according to claim 1 wherein said step of transferring wafersincludes:positioning the wafer carrier containing the wafers; moving thewafer tray upwardly and through an opening formed in the wafer carrier;lifting wafers from the wafer carrier onto the wafer tray.
 3. A methodfor processing wafers according to claim 1 and further comprisingplacing the loaded wafer tray at a loaded tray holding station.
 4. Amethod for processing wafers according to claim 1 wherein said step ofloading includes depositing the wafer carrier upon a carriage and movingthe wafer carrier into the enclosed work space.
 5. A method forprocessing wafers according to claim 1 wherein said step of loadingincludes moving a first carriage from a carrier load position to atransfer position.
 6. A method for processing wafers, comprising:loadingwafers held in a wafer carrier into an enclosed work space; transferringwafers from said wafer carrier to a wafer tray to produce a loaded wafertray having a plurality of wafers positioned thereon; said wafer trayproviding fluid access to surfaces of the wafers positioned thereon forprocessing; conveying the loaded wafer tray to and between multipleprocessing units which have access openings to said enclosed work space;storing unloaded wafer trays upon a first carriage for use in said stepof transferring wafers; moving the first carriage from a carrier loadposition wherein said wafer carrier loaded with wafers is loaded ontothe first carriage, to a tray pick position; elevating a stored unloadedwafer tray from the first carriage onto an elevator; moving the firstcarriage from the tray pick position to a pass-through position;lowering a wafer tray on said elevator through a pass-through opening inthe first carriage; moving the first carriage from the pass-throughposition to a transfer position wherein said first carriage is ready forsaid step of transferring.
 7. A method for processing wafers accordingto claim 6 and further comprising:after said step of transferringwafers, moving a second carriage to an extended tray load position;placing the loaded wafer tray at a loaded tray holding station upon saidsecond carriage.
 8. A method for processing wafers supplied upon a wafercarrier comprising:positioning a wafer tray on a movable head;positioning the wafer carrier containing the wafers in a transferposition; moving the wafer tray upwardly and through an opening formedin the wafer carrier; transferring wafers from the wafer carrier ontothe wafer tray to produce a loaded wafer tray; conveying the loadedwafer tray free from the wafer carrier to at least one processing unit;processing the loaded wafer tray in said at least one processing unit.9. A method for processing wafers according to claim 8 and furthercomprising placing the loaded wafer tray at a loaded tray holdingstation capable of inventorying a plurality of loaded wafer trays.
 10. Amethod for processing wafers according to claim 8 and further comprisingstoring unloaded wafer trays for use in said step of positioning thewafer tray on a movable head.
 11. A method for processing wafersaccording to claim 8 and further comprising:storing unloaded wafer traysupon a carriage for use in said step of positioning the wafer tray on amovable head; moving the carriage into a tray pick position; elevating astored unloaded wafer tray from said carriage; moving the carriage fromthe tray pick position to a transfer position wherein said carriage isready for said step of transferring.
 12. A method for processing wafersaccording to claim 8 and further comprising:storing unloaded wafer traysupon a first carriage for use in said step of positioning the wafer trayon a movable head; elevating a stored unloaded wafer tray from the firstcarriage onto an elevator; said head being a part of said elevator;moving the first carriage from the tray pick position to a pass-throughposition; lowering a wafer tray on said elevator through a pass-throughopening in the first carriage; moving the first carriage from thepass-through position to a transfer position wherein said first carriageis ready for said step of transferring.
 13. A method for processingwafers according to claim 8 and further comprising:storing unloadedwafer trays upon a first carriage for use in said step of positioningthe wafer tray on a movable head; elevating a stored unloaded wafer trayfrom the first carriage onto an elevator; said head being a part of saidelevator; moving the first carriage from the tray pick position to apass through position; lowering a wafer tray on said elevator through apass-through opening in the first carriage; moving the first carriagefrom the pass-through position to a transfer position wherein said firstcarriage is ready for said step of transferring; after said transferringwafers, moving a second carriage to an extended tray load position;placing the loaded wafer tray at a loaded tray holding station upon saidsecond carriage.
 14. A method for wafer tray and wafer tray engagementtool interaction, comprising:holding wafers in a wafer tray having atleast one longitudinal engagement feature which extends along the wafertray in the form of at least one recessed channel; positioning a waferengagement tool adjacent to said wafer tray; said wafer engagement toolhaving a main part and an engagement extension connected to the mainpart so as to be cantilevered therefrom; said engagement extensiondefining at least one engagement edge; moving the wafer engagement toollongitudinally along said at least one recessed channel; engaging saidwafer engagement tool with the wafer tray to prevent relativelongitudinal motion therebetween; lifting the wafer engagement tool andengaged wafer tray; moving the wafer engagement tool and engaged wafertray to a processing station; orienting the angular orientation of thewafer tray to enable the wafer tray to be positioned into a processingchamber forming part of the processing station; loading the wafer trayinto the processing chamber by sliding the wafer tray into an engagedrelationship with complementary parts contained in a rotor mounted forrotation within the processing chamber, said complementary partsincluding wafer tray engagement features which are at least partiallyreceived within said recessed channels.
 15. A method for processingwafers, comprising:opening an enclosure door forming part of anenclosure envelope, said enclosure envelope providing a substantiallyenclosed working space therewithin; loading a wafer carrier containing aplurality of wafers through the enclosure door; closing the enclosuredoor; positioning the wafer carrier containing the plurality of wafersin a transfer position; transferring the plurality of wafers from thewafer carrier by engaging an array of wafer receivers directly againstthe wafers to support the plurality of wafers upon the array of waferreceivers; conveying the plurality of wafers supported by the array ofwafer receivers away from the wafer carrier and onto at least oneprocessing station having an access opening which opens to the enclosedworking space; processing the plurality of wafers supported by the arrayof wafer receivers within said at least one processing station.
 16. Amethod for processing wafers according to claim 15 wherein said array ofwafer receivers is a tray having an array of wafer receivers formedtherein.
 17. A method for processing wafers according to claim 15 andfurther comprising:conveying the plurality of wafers supported by thearray of wafer receivers to at least two processing stations.
 18. Amethod for processing wafers according to claim 15 and furthercomprising:conveying the plurality of wafers supported by the array ofwafer receivers to at least two processing stations; thereafterconveying the plurality of wafers supported by the array of waferreceivers to an interface section; thereafter transferring the pluralityof wafers supported by the array of wafer receivers to a wafer carrier.19. A method for processing wafers according to claim 15 and furthercomprising:conveying the plurality of wafers supported by the array ofwafer receivers to at least two processing stations; thereafterconveying the plurality of wafers supported by the array of waferreceivers to an interface section; thereafter transferring the pluralityof wafers supported by the array of wafer receivers to a wafer carrierto provide a wafer carrier containing processed wafers; thereafteropening an enclosure door; removing the wafer carrier containingprocessed wafers from the enclosure.
 20. A method for processing wafersaccording to claim 15 wherein said at least one processing stationincludes a rotor upon which the plurality of wafers supported by thearray of wafer receivers rotates during at least a portion of theprocessing step.
 21. A method for processing wafers according to claim15 wherein said array of wafer receivers is a tray having an array ofwafer receivers formed therein.
 22. A method for processing wafersaccording to claim 15 wherein said step of transferring the plurality ofwafers includes:extending the array of wafer receivers upwardly andthrough an opening formed in the wafer carrier; lifting wafers from thewafer carrier onto the array of wafer receivers.
 23. A method forprocessing wafers according to claim 15 and further comprising placingthe plurality of wafers supported by the array of wafer receivers at aninventory station which can hold more than one such array of waferreceivers with the plurality of wafers supported thereon.
 24. A methodfor processing wafers according to claim 15 wherein said step of loadinga wafer carrier includes depositing the wafer carrier upon a carriageand moving the wafer carrier into the enclosed work space upon saidcarriage.
 25. A method for processing wafers according to claim 15wherein said step of loading includes moving a first carriage from acarrier load position to within the working space.
 26. A method forprocessing wafers according to claim 15 wherein said array of waferreceivers is a tray having an array of wafer receivers formed therein,and further comprising:storing unloaded wafer trays upon a firstcarriage for use in said step of transferring wafers; moving the firstcarriage from a carrier load position wherein said wafer carrier loadedwith wafers is loaded onto the first carriage, to a tray pick position;elevating a stored unloaded wafer tray from the first carriage; movingthe first carriage from the tray pick position to a transfer positionwherein said first carriage is ready for said transferring.
 27. A methodfor processing wafers according to claim 15 wherein said array of waferreceivers is a tray having an array of wafer receivers formed therein,and further comprising:storing unloaded wafer trays upon a firstcarriage for use in said step of transferring wafers; moving the firstcarriage from a carrier load position wherein said wafer carrier loadedwith wafers is loaded onto the first carriage, to a tray pick position;elevating a stored unloaded wafer tray from the first carriage onto anelevator; moving the first carriage from the tray pick position to apass-through position; lowering a wafer tray on said elevator through apass-through opening in the first carriage; moving the first carriagefrom the pass-through position to a transfer position wherein said firstcarriage is ready for said step of transferring.
 28. A method forprocessing wafers according to claim 27 and further comprising:aftersaid step of transferring the plurality of wafers, moving a secondcarriage to an extended tray load position; placing the loaded wafertray at a loaded tray holding station upon said second carriage.